Environmental Engineering Reference
In-Depth Information
hundreds of CCP forms per day. Individuals who handle large quantities of
photocopy paper, conduct photocopying activities, or use laser printers
extensively may be at special risk of developing upper respiratory symptoms.
d. TVOC exposures.
A variety of volatile organic compounds (VOCs)
may produce combined total VOC (TVOC) exposures during early building
occupancy sufficient in magnitude to cause mucous membrane irritation-
type symptoms. These TVOC exposures may be associated with solvent-type
odors characteristic of new or newly renovated buildings. Such exposures
diminish significantly with time and should resolve within several months.
It is difficult to diagnose a TVOC exposure building health problem from
environmental measurements since TVOCs represent such a broad range of
volatile organic compounds. However, TVOC concentrations >1 mg/m
3
may
be cause for concern.
e. Formaldehyde exposures.
Levels of HCHO in nonresidential build-
ings are usually relatively low. Elevated levels (>0.05 ppmv) may be associ-
ated with large quantities of office furniture whose components are bonded
with urea-formaldehyde resins. Classic symptoms, as previously described,
are irritation of the eyes and mucous membranes of the upper respiratory
system, headache, and fatigue. Both concentrations and symptoms may
increase or decrease with changes in temperature and relative humidity.
f. Mold infestation.
Various levels of mold infestation occur in prob-
lem buildings. These include localized problems associated with leaking
roofs, plumbing, and HVAC systems; groundwater seepage into sublevels;
moisture penetration of the building envelope; high relative humidity and
condensation problems associated with the improper operation of HVAC
systems; and infested HVAC system duct liners, condensate drip pans, and
filters. Infestation problems may be characterized by mold growth on build-
ing materials, furnishings, books, paper, etc., and, in some cases, elevated
airborne mold levels. Sampling airborne mold using both culturable/viable
and total mold spore sampling methods may be desirable to determine
dominant mold types present and their relative abundance. It is important
to realize that because mechanically ventilated buildings use recirculated air,
even poor quality filters remove mold spores sufficiently so that airborne
culturable/viable and total mold spore levels are typically low. Levels above
300 CFU/m
3
and 5000 S/m
3
indicate a potential infestation problem. Regard-
less of the results of air testing, the presence of significantly infested materials
indicates that a potential mold-related health problem may exist.
g. Surface dust.
A number of European studies have indicated a rela-
tionship between components of surface dust and building-related symp-
toms. The exact nature of this relationship needs to be better elucidated.
Studies in schools indicate that surface dust often contains elevated concen-
trations of pet, and in some cases cockroach, allergens. Pet allergens (cat and
